NEW YORK - Relatives of September 11 victims asked the FBI on Monday to brief them on its probe into allegations that News Corp. journalists sought to hack into terror victims' phones.

The allegation surfaced in the British newspaper The Daily Mirror last week, quoting an unnamed source. The paper reported that an American investigator had been approached by News of the World journalists offering money for phone records of the dead, but he turned them down.

The News of the World tabloid was shut down after it was accused of hacking into the phones of public figures and crime victims.

The FBI launched a preliminary inquiry into the matter after U.S. Rep. Peter King, a New York Republican, and other members of Congress wrote to FBI Director Robert Mueller demanding action.

The phone hacking scandal continued to roil London on Monday as a second official at Scotland Yard resigned and Prime Minister David Cameron called an emergency session of Parliament to address the crisis.

Mayor Michael Bloomberg said Monday that he was not aware of any allegation of improprieties in the US.

Sally Regenhard, whose firefighter son, Christian, was killed in the 2001 attacks, said she's been fielding phone calls from concerned family members of September 11 victims. She said there's a lot of confusion and the families want an update on what investigators know so far.

Lawyer Norman Siegel, who has represented September 11 victims' families in several civil cases, sent the letter on behalf of the families to Mueller, Attorney General Eric Holder and U.S. Rep. John Conyers of Michigan. Conyers is the ranking Democratic member of the House Judiciary Committee.

Kathy Wright, a spokeswoman for the FBI, said there's been ongoing communication since September 11, 2001, between the agency and victims' families. But she declined to comment on the letter or the inquiry itself.

Officials with the other two offices did not immediately return calls for comment. A News Corp. spokesman in New York declined to comment.

In the letter, Siegel commended the FBI for opening a preliminary inquiry and said the families wanted more information about its scope, goals and timetable. He said the family members were eager to cooperate with authorities to determine if any hacking was attempted or took place.